Urinary sediment cast scoring index for acute kidney injury: a pilot study.
OBJECTIVE
Urine microscopy is a useful diagnostic tool; however, the manner in which nephrologists prepare and examine urinary sediment is variable. We developed an acute kidney injury (AKI) cast scoring index (CSI) in order to standardize urinary microscopy. Further, we sought to assess the precision of this scoring system.


METHODS
Urine from 30 patients with AKI consistent with the syndrome of acute tubular necrosis were collected. Sample preparation was uniform and standardized. A panel of 3 nephrologists blinded to the sample preparation were instructed to grade each slide using the AKI CSI. Subsequently, the AKI CSI was then tested in another 18 patients with AKI to determine if this score could predict nonrenal recovery.


RESULTS
The inter-observer agreement index was 99.80%, with a coefficient of variation of 1.24%. Of the 90 paired observations, 98.8% fell within 2 standard deviations of the mean, signifying good agreement. The receiver operator characteristic area under the curve for AKI CSI to predict nonrenal recovery was 0.79.


CONCLUSIONS
AKI CSI is a simple, novel, reliable scoring system to grade the degree of epithelial cell and granular casts present on urine microscopy. A standardized AKI CSI has the potential to incorporate urinary cast analysis into the advancing field of AKI diagnostics. These preliminary data endorse the notion that the AKI CSI may be useful in predicting renal outcomes.
Chawla
Lakhmir S
LS
Department of Critical Care Medicine and Anesthesiology, George Washington University Medical Center, Washington, DC 20037, USA. lchawla@mfa.gwu.edu
Dommu
Aaron
A
Berger
Alexandra
A
Shih
Shirley
S
Patel
Samir S
SS
D000368:Aged; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007683:Kidney Tubular Necrosis, Acute / Q000473:pathology* / Q000652:urine*; D008297:Male; D008853:Microscopy / Q000379:methods*; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods*; D016482:Urinalysis / Q000379:methods*; D014556:Urine / Q000166:cytology*